Has Venoarterial Ecmo Been Underutilized in Covid-19 Patients?

Coronavirus disease 2019 (COVID-19) is a pandemic that has affected more than 5,400,000 people in over 180 countries worldwide with more than 40,000 reported deaths. Typical presentation of severe forms of COVID-19 is bilateral pneumonia and, in some patients, an acute hypoxemic respiratory failure that can represent a significant therapeutic challenge for physicians. In these severe patients with profound hypoxemia and a near-normal respiratory system compliance, at least in the very early phase, different clinical scenarios can be observed, ranging from normal breathing (i.e., “silent” hypoxemia) to bilateral patchy ground-glass opacities requiring oxygen supply. Gattinoni et al. suggested that the different COVID-19 patterns are related to the interaction of many factors, including the viral load, the host response, the physiological reserve and existing comorbidities, time between the onset of the disease and the presentation to the hospital, as well as provided therapies. Whether the interactions between these factors can really result in 2 different phenotypes of respiratory failure (i.e., the “L type,” characterized by low elastance, low ventilation-to-perfusion ratio, and low recruitability and the “H type,” characterized by high elastance, high right-to-left shunt, and high recruitability) remains to be demonstrated. Nevertheless, in some patients, the use of mechanical ventilation, even if adjusted on patient’s phenotype, fails to provide an adequate systemic oxygenation and rescue therapies might be needed.